In the past I've created generic (cocktail) bezels for my arcade setup, but I had to add the definition to the horizont.lay and vertical.lay files, and then (re)compile MAME. Is it possible do simply do this from the artwork directory in stead, e.g. by creating a horizont.zip and vertical.zip file containing the artwork and .lay files? If not, would it be possible to add such a feature so people can add their own generic screen definitions?

It's a kind of "here be dragons" thing, especially at the moment with options system in flux. If you do want to try, remember that you have to consider the possibility of multi-screen systems, and not break things by default. You definitely don't want to do something that will cause it to choose an unsuitable view when a person launches an unfamiliar system. Consider Nichibutsu mahjongs with private player LCDs, dual-screen Cave games, punch-out, etc. You need to ensure that whatever you do won't make it easy to cause one of these to come up with important stuff hidden.

Thanks for the warnings; you raise valid points here that I'll keep in mind when having a crack at this. I figure that when/if I manage to figure out how best to do it, I can easily do it again on the next code base, and create a patch for the current code.

No, that's not at all what I was talking about. Adding an implicit search path is just going to be confusing. It requires additional options:* Something like -fallback_artwork NAME that will make that artwork get loaded if there is no internal layout for the driver and no external artwork for the driver* Something like -override_artwork NAME that will force loading specified artwork, overriding internal layout and external artwork for the driver

Then if you want generic artwork for horizontal games as a fallback, you add "fallback_artwork horizontal" to your horizontal.ini (or whatever it's called these days), etc.

* Something like -fallback_artwork NAME that will make that artwork get loaded if there is no internal layout for the driver and no external artwork for the driver

In accordance with the current implementation, there's always an internal layout for the driver, assuming no game uses more than 4 screens. It could be a fall back in case no external artwork exists, but the user would need to make sure that the fallback artwork matches the screen setup (number of screens, orientation, etc.), since that information is not directly available in the artwork itself.